AI 中文总结
该研究在太赫兹量子级联激光器构成的量子行走梳状激光器平台中，通过次谐波锁定方案，以微波注入实现梳间距调谐，利用双音混频动态控制梳带宽与光谱形状，为高FSR腔的宽带可重构半导体梳状生成提供了新途径。
AI 中文摘要
片上频率梳在激光科学及各类应用中的重要性日益提升，宽带宽和平顶光谱包络对精密光谱学和密集波分复用通信尤为关键。为实现这些目标，有源微波调制已成为在光源处生成、稳定和重构频率梳的有力策略，但与高频调制相关的实际挑战对可及的腔自由光谱范围（FSR）施加了上限。本文中，我们在量子行走梳状激光器（一种新近推出的宽带且高度可控的梳状态平台）中展示了一种次谐波锁定方案。利用太赫兹环形量子级联激光器，我们在强微波注入下于腔往返频率的连续次谐波处实现了量子行走梳状生成，将梳间距从15.8 GHz调谐至1.58 GHz。所产生的态源于激光腔中的快增益动力学和非线性微波混频，通过双音注入，我们利用该混频动态控制梳带宽和光谱形状。这些结果确立了次谐波激发作为高FSR腔中宽带、可重构半导体梳状生成的一条途径。
英文摘要
On-chip frequency combs are increasingly relevant to both laser science and applications. Broad bandwidths and flat-top spectral envelopes are especially desirable for precision spectroscopy and dense wavelength-division multiplexed communications. Toward these goals, active microwave modulation has emerged as a powerful strategy for generating, stabilizing, and reconfiguring frequency combs at the source. However, practical challenges associated with high-frequency modulation imposes an upper bound on the accessible cavity free spectral ranges. Here, we demonstrate a subharmonic locking scheme in a quantum walk comb laser, a recently introduced platform for broadband and highly controllable comb states. Using a THz ring quantum cascade laser, we realize quantum walk comb formation under strong microwave injection at successive subharmonics of the cavity round-trip frequency, tuning the comb spacing from 15.8 to 1.58 GHz. The resulting states arise from fast-gain dynamics and nonlinear microwave mixing in the laser cavity. Through two-tone injection, we exploit this mixing to dynamically control the comb bandwidth and spectral shape. These results establish subharmonic excitation as a route to broadband, reconfigurable semiconductor comb generation in high-FSR cavities.
